The BGP specification suggests implementations should have three tables: the adj-rib-in, the loc-rib, and the adj-rib-out. The first of these three tables should contain the routes (NLRIs and attributes) transmitted by each of the speaker’s peers. The second table should contain the calculated best paths; these are the routes that will be (or are) installed…

When rolling out a new protocol such as IPv6, it is useful to consider the changes to security posture, particularly the network’s attack surface. While protocol security discussions are widely available, there is often not “one place” where you can go to get information about potential attacks, references to research about those attacks, potential counters,…

Today, an update on some compelling projects at IETF 102. Ours guest are Jeff Tantsura and Russ White. We review the following projects to see what’s new and understand what problems they’re solving: RIFT (Routing In Fat Trees), BIER (Bit Indexed Explicit Replication), PPR (Preferred Path Routing), and YANG data modeling. We also look at…

BGP is one of the foundational protocols that make the Internet “go;” as such, it is a complex intertwined system of different kinds of functionality bundled into a single set of TLVs, attributes, and other functionality. Because it is so widely used, however, BGP tends to gain new capabilities on a regular basis, making the…

Many network engineers find the entire world of telecom to be confusing—especially as papers are peppered with a lot of acronyms. If any part of the networking world is more obsessed with acronyms than any other, the telecom world, where the traditional phone line, subscriber access, and network engineering collide, reigns as the “king of…

Anyone who has worked with OSPF for any length of time has at least heard of areas—but perhaps before diving into Topology Transparent Zones (TTZs), a short review is in order. In this diagram, routers A and B are in area 0, routers C and D are Area Border Routers (ABRs), and routers E, F,…

I have not counted the IETF’s I have attended; I only know the first RFC on which I’m listed as a co-author was published in 2000, so this must be close to 20 years of interacting with the IETF community. I’m pretty certain I’ve attended at least two meetings a year in some years, and…

Low latency is coming to a network near you. In fact, it’s probably coming to your network, whether or not you realize it. This article was cross posted at APNIC While bandwidth has always been the primary measure of a network, and cross sectional or non-contending bandwidth for data center fabrics, further research and reflection…

On a recent history of networking episode, Alia talked a little about Maximally Redundant Trees (MRTs), and the concept of Depth First Search (DFS) numbering, along with the idea of a low point. While low points are quickly explained in my new book in the context of MRTs, I thought it worthwhile to revisit the…